1. Field of the Invention
The present invention relates to hydrogen generation devices. More particularly, to a hydrogen supplemental system and a method for increasing combustion efficiency in the combustion chamber of diesel or other internal combustion engines and lowering particulate matter and other emissions at idle.
2. Description of the Related Art
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition and burn the fuel that has been injected into the combustion chamber of the engine. The diesel engine has a higher thermal efficiency of any standard internal or external combustion engine due to its high compression ratio. Low-speed diesel engines as used in ships and other applications where overall engine weight is unimportant may have a thermal efficiency that exceeds approximately 50%. When in an idle state, a vehicle's main propulsion engine continues to operate while the vehicle is stopped. Idling is common in traffic conditions, especially during urban driving, such as at traffic lights or in stop-and-go driving during traffic congestion. However, idling periods in traffic are relatively short. There is more concern over long periods of idling of heavy-duty diesel engines while the vehicle is parked and not in active state. These long periods of idling have an adverse environmental impact and are a source of significant pollution and often unnecessary fuel consumption.
The idling periods in traffic, cause vehicles to emit significant amounts of pollution including, for example, nitrogen oxides (NOx) and volatile organic compounds (VOCs) which contribute to the formation of ozone smog; poisonous carbon monoxide; and particulate matter (PM) which contributes to asthma, heart disease, lung damage, and cancer. Recently, an effort has been made to reduce the amount of time that engines spend idling mainly due to fuel economy and emissions concerns, although some engines can also be damaged if kept idling for extended periods.
A major source of idle emissions are long-haul trucks, which are routinely idled overnight, mainly to provide cab heating and air conditioning. In addition to heat and air conditioning, truck accessories such as stereos, short distance radio communication systems such as citizen band radios (CBs), interior lights, televisions, computers and refrigerators demand power and can motivate idling even if climate control via the heating and air conditioning is unnecessary. In extreme cases, up to 6 kW of peak electrical power demand may be needed if multiple accessories are used at once.
Another significant source of diesel idle emissions can be railway locomotives. Unlike trucks, most locomotive engines do not use anti-freeze in their cooling systems. Thus, locomotives must idle their engines when the temperature drops below about 4° C. (40° F.) to prevent freezing of engine cooling water, thickening of engine oil and fuel and to maintain battery charge. At temperatures above 4° C., locomotives may idle to maintain a readily available engine, and/or to maintain comfortable temperatures inside the operator cab.
In yet another example, motor coach buses are another vehicle category that can experience long periods of idling of their main propulsion engine. This is primarily to maintain a comfortable interior compartment for passengers (heat or air conditioning). While not as numerous as trucks, coaches have attracted attention because, due to their large interior compartment, maintaining a comfortable interior temperature requires substantially more idling time than the typical long-haul truck or personal passenger vehicle.
Diesel engines and gasoline engines run more efficiently when they are operated under-load and at appropriate operating temperatures. They are highly inefficient at idle. A diesel engine at idle creates a disproportionately larger amount of harmful emissions, including CO, Nox and PM, and waste a greater amount of fuel than operation at load. The particulates also been reported to be much smaller (20 nm) than those at load (60 nm).
Although there is an understanding that hydrogen could be a substitute for gasoline in internal combustion engines, the conventional systems implementing the use of hydrogen typically produces the hydrogen and oxygen in a combined gas stream. The hydrogen and oxygen in the combined hydrogen and oxygen gas stream are not separated from each other and are known as HHO or Brown's gas. The use of HHO or Brown's gas in the case of modern gasoline powered vehicles is problematic for several reasons including interference with modern anti-pollution apparatus. Specifically the extra oxygen in the combined hydrogen and oxygen gas stream is detected by the vehicle's oxygen sensor which communicates this extra oxygen level to an on-board computer, namely and Electronic Control Unit (ECU) of the vehicle. The ECU then makes adjustments based on this detection including increasing the amount of gasoline being injected, thereby defeating any supposed fuel savings.
Diesel exhaust is composed of two phases gas and particles and both phases contribute to a significant health risk in human beings. The gas phase is composed of many of the urban hazardous air pollutants, such as acetaldehyde, acrolein, benzene, 1,3-butadiene, formaldehyde and polycyclic aromatic hydrocarbons. The particle phase also has many different types of particles that can be classified by size or composition. The size of diesel particulates that are of greatest health concern are those that are in the categories of fine, and ultrafine particles. The composition of these fine and ultrafine particles may be composed of elemental carbon with adsorbed compounds such as organic compounds, sulfate, nitrate, metals and other trace elements. Although the majority of the emissions from diesel engines are in the combustion process itself, most of the particulate emissions are the result of incomplete combustion. This is because all of the fuel injected into the combustion chamber is not burned. As a result unburned particulates and other emissions are inherent in diesel engines. Diesel exhaust is emitted from a broad range of diesel engines; the on-road diesel engines of trucks, buses and cars and the off-road diesel engines that include locomotives, marine vessels and heavy duty equipment.
The current technology to reduce particulate matter is either particulate exhaust filters or exhaust systems that attempt to burn the particulate matter once it reaches the exhaust. The use of exhaust filters require active monitoring to determine whether the exhaust filters have reached their maximum capacity. Further, the exhaust systems that burn the particulate matter are typically complex and expensive system.